Larry Rivers's painting, Washington Crossing The Delaware, is more John Ford than John Singleton Copley. His other richly-textured works, such as Last Civil War Veteran, also manage to suggest Walt Whitmanesque cadences: "Behold the brown-faced men, each group, each person a picture... While, scarlet and blue and snowy white, the guidon flags flutter gaily in the wind." In other words, Rivers, who has died aged 78 of liver cancer, was a relaxed and representative American talent.

This is confirmed by the life. Born Yitzroch Luiza Grossberg, to immigrant parents in the Bronx, he became a professional jazz musician in 1940 and, he claimed, acquired his public name when an emcee called for a big hand for "Larry Rivers and his Mudcats". He joined the US army air corps band in 1942, was discharged as medically unfit, and studied at the Juilliard School of Music in New York, where his friendship with Miles Davis brought him engagements with great musicians such as Charlie Parker.

Simultaneously, he discovered an interest in painting through an encounter with a musical motif based on a painting by Braque. He studied art under the legendary Hans Hofmann at his school on Eighth Street, and then under William Baziotes at New York University.

It may be that Rivers's last metamorphosis, from painter to writer, produced his masterpiece: What Did I Do? The Unauthorised Autobiography Of Larry Rivers (written with Arnold Weinstein, 1992). This Rabelaisian account of his jazz, his drug-taking, his sexual encounters - he was heterosexual, but would do anything to oblige a male friend - his suicide attempt, and, inter alia, his painting, is among the funniest and most liberated books of the 20th century. There is not a malicious sentence in it, but seeing what he does to his friends without malice, it hardly matters: names are named.

In painting, Rivers was by no means an American isolationist. Braque and Hofmann (a German-born acquaintance of the Fauves and Cubists) give the clue. In England, his closest contemporary stylistically was Peter Blake: similar impressionist touch; similar oblique, often humorous, view of their subjects; similar acceptance of the demotic or banal as fitting matters for art - which was to become the trademark of pop art.

The freshly brushed surface of his canvases, and the finesse of his draughtsmanship, indicate a cultivated response to a wide range of visual experience, certainly including the work of Pollock, de Kooning, Guston, Baziotes and the generation of abstract expressionists who preceded him, but, more pertinently, reflecting an encounter with Bonnard during a visit to Europe in the 1950s.

The elision from musician to painter was smooth enough in one sense. The Five Spot, on 10th Street, where Rivers played saxophone, was in the heart of New York's bohemia, close by Hofmann's school, and was one of the clubs habituated by the painters who, from 1947, were to make New York the centre of the art world.

But Rivers's work flowed more slowly in finding widespread acceptance than that of either his predecessors or immediate successors, the pop artists. Though he is often bracketed with pop, because his imagery was adapted from material like American civil-war photographs, advertising hoardings, Buick cars and commercial packaging, he was often too poor to paint cans of Campbell soup; he consumed their contents instead. His work fell between the two movements, and in the Martini belt, where clear identity was essential to recognition, that was not helpful.

In his sense of technique and touch, Rivers was much more of a European painter than most American pop artists. In a review of his first show, in 1949, Clement Greenberg, never known to throw a bone to pop, wrote of the "superb plenitude and sensuousness" of his painting and, wrongly, that he was "a better composer of pictures than was Bonnard himself" (Bonnard, of course, was innovative and committed to a lifetime of painting; Rivers was a tad conventional and liable to sloppiness).

He exhibited at the 1954 Sao Paulo Bienal, and mounted a retrospective show which travelled around five big-city galleries in the US. His worldly success was confirmed when the Marlborough-Gerson gallery opened in New York in 1963, and signed him up along with Rothko and de Kooning. At the opening party, Rivers was served with a subpoena for deserting the Tibor de Nagy gallery, a departure he lived to regret because John Myers, of Tibor de Nagy, had promoted and supported his work vigorously. The price of Marlborough kudos was that you could be left to stay afloat on the raft of your critical reception, or sink.

These years marked the peak of Rivers's career. He was painting canvases with motifs taken from Camel cigarette packets, Confederate flags, and Dutch Masters cigars, which had a version of Rembrandt's Board Of The Drapers Guild on the packet - so that the Rivers version willy-nilly illustrated the thesis of the American-based British critic Lawrence Alloway about the continuum between popular culture and pop (fine art) culture. Rivers himself denied any intention of reflecting mass culture: "I have a bad arm, and am not interested in the art of holding up mirrors."

In the 1960s, he became friendly with Andy Warhol, who took a verbal snapshot of him as a motorbike-riding, party-going humorist. "I'd heard that when he was about to go on The $64,000 Question on TV," Warhol wrote, "he passed the word around that if he won, you could find him at the Cedar bar, and if he lost, he'd head straight for the Five Spot, where he played jazz saxophone." Rivers won $49,000, and went straight to the Cedar to buy drinks for around 300 people.

He designed stage sets for the play Try, Try!, by his friend and sexual partner Frank O'Hara, and sets and costumes for a New York Philharmonic performance of Stravinsky's Oedipus Rex. He worked on a television travelogue about Africa, before being arrested as a suspected mercenary in Nigeria in 1968 and, apparently, nearly executed. Newsday reviewed the television film, and commented perceptively that it was "something like a Rivers canvas: complex, brilliantly colourful, and maybe too tongue-in-cheek for serious consideration".

Rivers's work included sculpture, video, and painting with air brush and spray cans, but it is the paintings of his first couple of decades that will be remembered. In Europe, he showed at Documenta 6, at Kassel, in 1979, following that up with a travelling retrospective in Germany in 1980-81. But he had no big show in Britain. Most people here first became acquainted with his work in the Tate Gallery's hit show of 1964, Painting and Sculpture of a Decade 54-64, in which he had a brilliant group of four paintings, including Last Civil War Veteran.

After the war, he married Augusta Burger and adopted her son. They had another son (who survives his father), but divorced soon afterwards, and, in 1961, he married Clarice, a Welsh-born teacher. They separated in 1967, but remained married and friendly. Rivers is also survived by their two daughters, and by a son he subsequently had with Daria Deshuk, a painter. For the last five years, he lived with Jeni Olin, a poet.

· Larry Rivers, painter and musician, born August 17 1923; died August 14 2002